Conventionally, as is disclosed in JP1994(06)-144000A, this type of vehicle door opening and closing apparatus is provided with a driving power source configured to generate a driving force relevant to an opening/closing movement of a vehicle door, an opening/closing mechanism for operating a vehicle door by a driving force of the driving power source in such a manner that an opening defined in a vehicle body is opened and closed, an operating means for outputting an operation signal in response to its operation, and a controlling means for controlling, on the basis of the operation signal, a driving of the driving power source. This apparatus is further provided with an overload-detecting means for detecting a load applied to the vehicle door. When the controlling means determines on the basis of a signal from the overload-detecting means that the vehicle door has been subjected to an overload, the controlling means implements a control by which a driving of the driving power source is ceased. This apparatus is still further provided with a vehicle door operation intention-detecting means for detecting an intention of a user to manually operate the vehicle door. When the controlling means has determined on the basis of a signal from the overload-detecting means that the vehicle door has been subjected to an overload, if the controlling means determines on the basis of a signal from the vehicle door operation intension-detecting means that a user intends to manually operate the vehicle door, the controlling means switches an actually running mode to a manual operation mode.
According to the above described vehicle door opening and closing apparatus, however, when a load being applied to the vehicle door is, for example, too great to manually open or close the vehicle door, the controlling means ceases driving the driving power source in response to a signal from the overload-detecting means. Therefore, it is not possible to open and close the vehicle door by use of a driving force of the driving power source, and is further not possible to open and close the vehicle door even manually. In such a case, there is a danger of the convenience, which is required upon opening and closing the vehicle door, of being deteriorated. Further, when a signal from the overload-detecting means is employed to control an obstacle entrapment detection while the vehicle door is being opened and closed, normally, the driving power source is controlled to generate an output value at a low level so that load applied to an entrapped obstacle can be restrained. Accordingly, it is obvious that convenience above described would be damaged.
The present invention has been made in view of the above circumstances, and provides a vehicle door opening and closing apparatus which is capable of assuring safety of an opening/closing operation of a vehicle door, and of enhancing convenience thereof.